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Myofibroblast expression in airways and alveoli is affected by smoking and COPD.

ABSTRACT: BACKGROUND: Chronic obstructive pulmonary disease (COPD) is characterized by structural changes in alveoli and airways. Our aim was to analyse the numbers of alpha-smooth muscle actin (?-SMA) positive cells, as a marker of myofibroblasts, in different lung compartments in non-smokers and smokers with normal lung function or COPD. METHODS: ?-SMA, tenascin-C (Tn-C) and EDA-fibronectin in alveolar level and airways were assayed by immunohistochemistry and quantified by image analysis. Immunohistochemical findings were correlated with clinical data. ?-SMA protein was also analysed by Western blotting from fibroblastic cells cultured from peripheral lung of non-smokers, smokers without COPD and smokers with COPD. RESULTS: In many cases, the endings of the detached alveolar walls were widened, the structures of which were named as widened alveolar tips. Widened alveolar tips contained ?-SMA positive cells, which were obviously myofibroblasts. There were less alveolar tips containing positive cells for ?-SMA in alveoli and ?-SMA positive cells in bronchioles in smokers and in COPD compared to non-smokers. The quantity of ?-SMA positive cells was increased in bronchi in COPD. Tn-C was elevated in bronchi in COPD and smokers' lung. The ?-SMA protein level was 1.43-fold higher in stromal cells cultured from non-smokers than in those of smokers. CONCLUSIONS: Myofibroblasts are localized variably in normal and diseased lung. This indicates that they have roles in both regeneration of lung and pathogenesis of COPD. The widened alveolar tips, these newly characterized histological structures, seemed to be the source of myofibroblasts at the alveolar level.

SUBMITTER: Karvonen HM

PROVIDER: S-EPMC3751100 | biostudies-literature | 2013

REPOSITORIES: biostudies-literature

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Myofibroblast expression in airways and alveoli is affected by smoking and COPD.

Karvonen Henna M HM Lehtonen Siri T ST Harju Terttu T Sormunen Raija T RT Lappi-Blanco Elisa E Mäkinen Johanna M JM Laitakari Kirsi K Johnson Shirley S Kaarteenaho Riitta L RL

Respiratory research 20130811

<h4>Background</h4>Chronic obstructive pulmonary disease (COPD) is characterized by structural changes in alveoli and airways. Our aim was to analyse the numbers of alpha-smooth muscle actin (α-SMA) positive cells, as a marker of myofibroblasts, in different lung compartments in non-smokers and smokers with normal lung function or COPD.<h4>Methods</h4>α-SMA, tenascin-C (Tn-C) and EDA-fibronectin in alveolar level and airways were assayed by immunohistochemistry and quantified by image analysis. ...[more]

PMID: 23937155

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Project description:Rationale: DNA methylation is an epigenetic modification that is highly disrupted in response to cigarette smoke and involved in a wide spectrum of malignant and non-malignant diseases, but surprisingly not previously assessed in small airways of patients with chronic obstructive pulmonary disease (COPD). Small airways are the primary sites of airflow obstruction in COPD. We sought to determine whether DNA methylation patterns are disrupted in small airway epithelia of COPD patients, and evaluate whether changes in gene expression are associated with these disruptions. Methods: Genome-wide methylation and gene expression analysis were performed on small airway epithelial DNA and RNA obtained from the same patient during bronchoscopy, using Illumina's Infinium HM27 and Affymetrix's Genechip Human Gene 1.0 ST arrays. To control for known effects of cigarette smoking on DNA methylation, methylation and gene expression profiles were compared between former smokers (FS) with and without COPD matched for age, pack years and years of smoking cessation. Results: Our results indicate that aberrant DNA methylation is i) a genome-wide phenomenon in small airways of patients with COPD and ii) associated with altered expression of genes and pathways important to COPD, such as the Nrf2 oxidative response pathway. Conclusions: DNA methylation is likely an important mechanism contributing to modulation of genes important to COPD pathology. Since these methylation events may underlie disease-specific gene-expression changes, their characterization is a critical first step towards the development of epigenetic markers and an opportunity for developing novel epigenetic therapeutic interventions for COPD. Bisulphite converted DNA from small airway (airways less than <2 mm in diameter) from 38 former smokers: 15 subjects with COPD (post bronchodilator FEV1/FVC ratio <70% and FEV1 predicted M-bM-^IM-$ 80%) and 21 with normal lung function, were hybridized to the Illumina Infinium 27k Human Methylation Beadchip.

Project description:BACKGROUND:Female smokers have increased risk for chronic obstructive pulmonary disease (COPD) compared with male smokers who have a similar history of cigarette smoke exposure. Tertiary lymphoid follicles are often found in the lungs of patients with severe COPD but sex-related differences have not been previously investigated. We determined the impact of female sex hormones on chronic cigarette smoke-induced expression of lymphoid aggregates in mice with COPD-like pathologies. METHODS:Lymphoid aggregate counts, total aggregate cross-sectional area and foamy macrophage counts were determined morphometrically in male, female, and ovariectomized mice exposed to air or cigarette smoke for 6?months. B-cell activating factor (BAFF) protein expression and markers of oxidative stress were evaluated in mouse lung tissues by immunofluorescence staining and gene expression analyses. Quantitative histology was performed on lung tissue sections of human COPD lungs to evaluate follicle formation. RESULTS:Lymphoid follicle and foamy macrophage counts as well as the total follicle cross-sectional area were differentially increased in lung tissues of female mice compared to male mice, and these differences were abolished by ovariectomy. These lymphoid aggregates were positive for CD45, CD20, CD21 and BAFF expression. Differential increases in Mmp12 and Cxcl2 gene expression correlated with an increase in foamy macrophages in parenchymal tissues of female but not male mice after smoke exposure. Parenchymal tissues from female mice failed to induce antioxidant-related genes in response to smoke exposure, and this effect was restored by ovariectomy. 3-nitrotyrosine, a stable marker of oxidative stress, positively correlated with Mmp12 and Cxcl2 gene expression. Hydrogen peroxide induced BAFF protein in mouse macrophage cell line. In human lung tissues, female smokers with severe COPD demonstrated increased numbers of lymphoid follicles compared with males. CONCLUSIONS:Chronic smoke exposure increases the risk of lymphoid aggregate formation in female mice compared with male mice, which is mediated female sex hormones and BAFF expression in an oxidative environment.

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Myofibroblast expression in airways and alveoli is affected by smoking and COPD.

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Myofibroblast expression in airways and alveoli is affected by smoking and COPD.

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